1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
4 */
5
6#include <linux/hashtable.h>
7#include <linux/xattr.h>
8#include "messages.h"
9#include "props.h"
10#include "btrfs_inode.h"
11#include "transaction.h"
12#include "ctree.h"
13#include "xattr.h"
14#include "compression.h"
15#include "space-info.h"
16#include "fs.h"
17#include "accessors.h"
18#include "super.h"
19#include "dir-item.h"
20
21#define BTRFS_PROP_HANDLERS_HT_BITS 8
22static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
23
24struct prop_handler {
25 struct hlist_node node;
26 const char *xattr_name;
27 int (*validate)(const struct btrfs_inode *inode, const char *value,
28 size_t len);
29 int (*apply)(struct btrfs_inode *inode, const char *value, size_t len);
30 const char *(*extract)(const struct btrfs_inode *inode);
31 bool (*ignore)(const struct btrfs_inode *inode);
32 int inheritable;
33};
34
35static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
36{
37 struct hlist_head *h;
38
39 h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
40 if (hlist_empty(h))
41 return NULL;
42
43 return h;
44}
45
46static const struct prop_handler *
47find_prop_handler(const char *name,
48 const struct hlist_head *handlers)
49{
50 struct prop_handler *h;
51
52 if (!handlers) {
53 u64 hash = btrfs_name_hash(name, strlen(name));
54
55 handlers = find_prop_handlers_by_hash(hash);
56 if (!handlers)
57 return NULL;
58 }
59
60 hlist_for_each_entry(h, handlers, node)
61 if (!strcmp(h->xattr_name, name))
62 return h;
63
64 return NULL;
65}
66
67int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
68 const char *value, size_t value_len)
69{
70 const struct prop_handler *handler;
71
72 if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
73 return -EINVAL;
74
75 handler = find_prop_handler(name, NULL);
76 if (!handler)
77 return -EINVAL;
78
79 if (value_len == 0)
80 return 0;
81
82 return handler->validate(inode, value, value_len);
83}
84
85/*
86 * Check if a property should be ignored (not set) for an inode.
87 *
88 * @inode: The target inode.
89 * @name: The property's name.
90 *
91 * The caller must be sure the given property name is valid, for example by
92 * having previously called btrfs_validate_prop().
93 *
94 * Returns: true if the property should be ignored for the given inode
95 * false if the property must not be ignored for the given inode
96 */
97bool btrfs_ignore_prop(const struct btrfs_inode *inode, const char *name)
98{
99 const struct prop_handler *handler;
100
101 handler = find_prop_handler(name, NULL);
102 ASSERT(handler != NULL);
103
104 return handler->ignore(inode);
105}
106
107int btrfs_set_prop(struct btrfs_trans_handle *trans, struct btrfs_inode *inode,
108 const char *name, const char *value, size_t value_len,
109 int flags)
110{
111 const struct prop_handler *handler;
112 int ret;
113
114 handler = find_prop_handler(name, NULL);
115 if (!handler)
116 return -EINVAL;
117
118 if (value_len == 0) {
119 ret = btrfs_setxattr(trans, inode: &inode->vfs_inode, name: handler->xattr_name,
120 NULL, size: 0, flags);
121 if (ret)
122 return ret;
123
124 ret = handler->apply(inode, NULL, 0);
125 ASSERT(ret == 0);
126
127 return ret;
128 }
129
130 ret = btrfs_setxattr(trans, inode: &inode->vfs_inode, name: handler->xattr_name, value,
131 size: value_len, flags);
132 if (ret)
133 return ret;
134 ret = handler->apply(inode, value, value_len);
135 if (ret) {
136 btrfs_setxattr(trans, inode: &inode->vfs_inode, name: handler->xattr_name, NULL,
137 size: 0, flags);
138 return ret;
139 }
140
141 set_bit(nr: BTRFS_INODE_HAS_PROPS, addr: &inode->runtime_flags);
142
143 return 0;
144}
145
146static int iterate_object_props(struct btrfs_root *root,
147 struct btrfs_path *path,
148 u64 objectid,
149 void (*iterator)(void *,
150 const struct prop_handler *,
151 const char *,
152 size_t),
153 void *ctx)
154{
155 int ret;
156 char *name_buf = NULL;
157 char *value_buf = NULL;
158 int name_buf_len = 0;
159 int value_buf_len = 0;
160
161 while (1) {
162 struct btrfs_key key;
163 struct btrfs_dir_item *di;
164 struct extent_buffer *leaf;
165 u32 total_len, cur, this_len;
166 int slot;
167 const struct hlist_head *handlers;
168
169 slot = path->slots[0];
170 leaf = path->nodes[0];
171
172 if (slot >= btrfs_header_nritems(eb: leaf)) {
173 ret = btrfs_next_leaf(root, path);
174 if (ret < 0)
175 goto out;
176 else if (ret > 0)
177 break;
178 continue;
179 }
180
181 btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: slot);
182 if (key.objectid != objectid)
183 break;
184 if (key.type != BTRFS_XATTR_ITEM_KEY)
185 break;
186
187 handlers = find_prop_handlers_by_hash(hash: key.offset);
188 if (!handlers)
189 goto next_slot;
190
191 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
192 cur = 0;
193 total_len = btrfs_item_size(eb: leaf, slot);
194
195 while (cur < total_len) {
196 u32 name_len = btrfs_dir_name_len(eb: leaf, s: di);
197 u32 data_len = btrfs_dir_data_len(eb: leaf, s: di);
198 unsigned long name_ptr, data_ptr;
199 const struct prop_handler *handler;
200
201 this_len = sizeof(*di) + name_len + data_len;
202 name_ptr = (unsigned long)(di + 1);
203 data_ptr = name_ptr + name_len;
204
205 if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
206 memcmp_extent_buffer(eb: leaf, XATTR_BTRFS_PREFIX,
207 start: name_ptr,
208 XATTR_BTRFS_PREFIX_LEN))
209 goto next_dir_item;
210
211 if (name_len >= name_buf_len) {
212 kfree(objp: name_buf);
213 name_buf_len = name_len + 1;
214 name_buf = kmalloc(name_buf_len, GFP_NOFS);
215 if (!name_buf) {
216 ret = -ENOMEM;
217 goto out;
218 }
219 }
220 read_extent_buffer(eb: leaf, dst: name_buf, start: name_ptr, len: name_len);
221 name_buf[name_len] = '\0';
222
223 handler = find_prop_handler(name: name_buf, handlers);
224 if (!handler)
225 goto next_dir_item;
226
227 if (data_len > value_buf_len) {
228 kfree(objp: value_buf);
229 value_buf_len = data_len;
230 value_buf = kmalloc(data_len, GFP_NOFS);
231 if (!value_buf) {
232 ret = -ENOMEM;
233 goto out;
234 }
235 }
236 read_extent_buffer(eb: leaf, dst: value_buf, start: data_ptr, len: data_len);
237
238 iterator(ctx, handler, value_buf, data_len);
239next_dir_item:
240 cur += this_len;
241 di = (struct btrfs_dir_item *)((char *) di + this_len);
242 }
243
244next_slot:
245 path->slots[0]++;
246 }
247
248 ret = 0;
249out:
250 btrfs_release_path(p: path);
251 kfree(objp: name_buf);
252 kfree(objp: value_buf);
253
254 return ret;
255}
256
257static void inode_prop_iterator(void *ctx,
258 const struct prop_handler *handler,
259 const char *value,
260 size_t len)
261{
262 struct inode *inode = ctx;
263 struct btrfs_root *root = BTRFS_I(inode)->root;
264 int ret;
265
266 ret = handler->apply(BTRFS_I(inode), value, len);
267 if (unlikely(ret))
268 btrfs_warn(root->fs_info,
269 "error applying prop %s to ino %llu (root %llu): %d",
270 handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
271 btrfs_root_id(root), ret);
272 else
273 set_bit(nr: BTRFS_INODE_HAS_PROPS, addr: &BTRFS_I(inode)->runtime_flags);
274}
275
276int btrfs_load_inode_props(struct btrfs_inode *inode, struct btrfs_path *path)
277{
278 struct btrfs_root *root = inode->root;
279 u64 ino = btrfs_ino(inode);
280
281 return iterate_object_props(root, path, objectid: ino, iterator: inode_prop_iterator,
282 ctx: &inode->vfs_inode);
283}
284
285static int prop_compression_validate(const struct btrfs_inode *inode,
286 const char *value, size_t len)
287{
288 if (!btrfs_inode_can_compress(inode))
289 return -EINVAL;
290
291 if (!value)
292 return 0;
293
294 if (btrfs_compress_is_valid_type(str: value, len))
295 return 0;
296
297 if ((len == 2 && strncmp("no", value, 2) == 0) ||
298 (len == 4 && strncmp("none", value, 4) == 0))
299 return 0;
300
301 return -EINVAL;
302}
303
304static int prop_compression_apply(struct btrfs_inode *inode, const char *value,
305 size_t len)
306{
307 struct btrfs_fs_info *fs_info = inode->root->fs_info;
308 int type;
309
310 /* Reset to defaults */
311 if (len == 0) {
312 inode->flags &= ~BTRFS_INODE_COMPRESS;
313 inode->flags &= ~BTRFS_INODE_NOCOMPRESS;
314 inode->prop_compress = BTRFS_COMPRESS_NONE;
315 return 0;
316 }
317
318 /* Set NOCOMPRESS flag */
319 if ((len == 2 && strncmp("no", value, 2) == 0) ||
320 (len == 4 && strncmp("none", value, 4) == 0)) {
321 inode->flags |= BTRFS_INODE_NOCOMPRESS;
322 inode->flags &= ~BTRFS_INODE_COMPRESS;
323 inode->prop_compress = BTRFS_COMPRESS_NONE;
324
325 return 0;
326 }
327
328 if (!strncmp("lzo", value, 3)) {
329 type = BTRFS_COMPRESS_LZO;
330 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
331 } else if (!strncmp("zlib", value, 4)) {
332 type = BTRFS_COMPRESS_ZLIB;
333 } else if (!strncmp("zstd", value, 4)) {
334 type = BTRFS_COMPRESS_ZSTD;
335 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
336 } else {
337 return -EINVAL;
338 }
339
340 inode->flags &= ~BTRFS_INODE_NOCOMPRESS;
341 inode->flags |= BTRFS_INODE_COMPRESS;
342 inode->prop_compress = type;
343
344 return 0;
345}
346
347static bool prop_compression_ignore(const struct btrfs_inode *inode)
348{
349 /*
350 * Compression only has effect for regular files, and for directories
351 * we set it just to propagate it to new files created inside them.
352 * Everything else (symlinks, devices, sockets, fifos) is pointless as
353 * it will do nothing, so don't waste metadata space on a compression
354 * xattr for anything that is neither a file nor a directory.
355 */
356 if (!S_ISREG(inode->vfs_inode.i_mode) &&
357 !S_ISDIR(inode->vfs_inode.i_mode))
358 return true;
359
360 return false;
361}
362
363static const char *prop_compression_extract(const struct btrfs_inode *inode)
364{
365 switch (inode->prop_compress) {
366 case BTRFS_COMPRESS_ZLIB:
367 case BTRFS_COMPRESS_LZO:
368 case BTRFS_COMPRESS_ZSTD:
369 return btrfs_compress_type2str(type: inode->prop_compress);
370 default:
371 break;
372 }
373
374 return NULL;
375}
376
377static struct prop_handler prop_handlers[] = {
378 {
379 .xattr_name = XATTR_BTRFS_PREFIX "compression",
380 .validate = prop_compression_validate,
381 .apply = prop_compression_apply,
382 .extract = prop_compression_extract,
383 .ignore = prop_compression_ignore,
384 .inheritable = 1
385 },
386};
387
388int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
389 struct btrfs_inode *inode,
390 const struct btrfs_inode *parent)
391{
392 struct btrfs_root *root = inode->root;
393 struct btrfs_fs_info *fs_info = root->fs_info;
394 int ret;
395 int i;
396 bool need_reserve = false;
397
398 if (!test_bit(BTRFS_INODE_HAS_PROPS, &parent->runtime_flags))
399 return 0;
400
401 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
402 const struct prop_handler *h = &prop_handlers[i];
403 const char *value;
404 u64 num_bytes = 0;
405
406 if (!h->inheritable)
407 continue;
408
409 if (h->ignore(inode))
410 continue;
411
412 value = h->extract(parent);
413 if (!value)
414 continue;
415
416 /*
417 * This is not strictly necessary as the property should be
418 * valid, but in case it isn't, don't propagate it further.
419 */
420 ret = h->validate(inode, value, strlen(value));
421 if (ret)
422 continue;
423
424 /*
425 * Currently callers should be reserving 1 item for properties,
426 * since we only have 1 property that we currently support. If
427 * we add more in the future we need to try and reserve more
428 * space for them. But we should also revisit how we do space
429 * reservations if we do add more properties in the future.
430 */
431 if (need_reserve) {
432 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items: 1);
433 ret = btrfs_block_rsv_add(fs_info, block_rsv: trans->block_rsv,
434 num_bytes,
435 flush: BTRFS_RESERVE_NO_FLUSH);
436 if (ret)
437 return ret;
438 }
439
440 ret = btrfs_setxattr(trans, inode: &inode->vfs_inode, name: h->xattr_name, value,
441 strlen(value), flags: 0);
442 if (!ret) {
443 ret = h->apply(inode, value, strlen(value));
444 if (ret)
445 btrfs_setxattr(trans, inode: &inode->vfs_inode, name: h->xattr_name,
446 NULL, size: 0, flags: 0);
447 else
448 set_bit(nr: BTRFS_INODE_HAS_PROPS, addr: &inode->runtime_flags);
449 }
450
451 if (need_reserve) {
452 btrfs_block_rsv_release(fs_info, block_rsv: trans->block_rsv,
453 num_bytes, NULL);
454 if (ret)
455 return ret;
456 }
457 need_reserve = true;
458 }
459
460 return 0;
461}
462
463int __init btrfs_props_init(void)
464{
465 int i;
466
467 for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
468 struct prop_handler *p = &prop_handlers[i];
469 u64 h = btrfs_name_hash(name: p->xattr_name, strlen(p->xattr_name));
470
471 hash_add(prop_handlers_ht, &p->node, h);
472 }
473 return 0;
474}
475
476

source code of linux/fs/btrfs/props.c